A colleague is leaving where I work. Nothing unusual there except that when we discuss her leaving and the hole it will leave in our team, we only discuss it in terms of her expertise. Which is fair enough. But she is the only non-white person on our team and one of the very few non-white people employed in a position of responsibility. I think we're all aware of that but somehow we're just not talking about it. Maybe it just too impolite... I don't know. Even I don't talk about it and I'm not usually known for my politeness.